A young investigator proposes a five-year research plan to continue studies in the perception of speech and complex sounds by persons with sensorineural hearing loss. A general model of sensorineural hearing loss is described that is based upon deficits in the audibility of speech cues and deficits in the spectral resolution of those cues (Turner and Henn, 1988). The model provides an "internal spectral representation" of a speech segment for each subject that describes the audibility and perceptual strength of spectral cues. This internal representation is derived by calculating the outputs of a bank of auditory filters; the characteristics of these filters are determined individually for each subject. The internal representations are then used to predict the confusions that subjects make on a speech recognition task, testing the hypothesis that the stronger the resemblance between two internal spectra in a given subject. The more often those two speech sounds will be confused by that subject. Several measures of auditory filtering will be used to refine the model, as well as several schemes, based upon speech perception research, for quantifying the "similarity" of speech spectra. The goal of speech processing for the hearing impaired that follows from such a hypothesis is to operate upon the physical speech signal in such a manner as to produce an internal representation in the ear that quantitatively provides speech cues most like that produced in the normal ear. Several additional experiments are proposed to test the potential applicability of "multi- channel"models of complex sound perception (profile-analysis); both behavioral and physiological experiments are described.